The invention relates to robotic devices and methods, and more particularly to a mobile drive unit for transporting a payload.
Movement of products in a modern warehouse environment, such as a package sort center, in which packages are moved within a facility, occurs on a vast scale. One means to sort packages (i.e., payloads) is to use mobile drive units to deliver packages to destinations designated by the ultimate final destination of the package. For example, mobile drive units can be used to organize packages based on delivery route, as determined based on a postal code or other package features. Mobile drive units are self-powered robotic devices that travel on the floor of the warehouse guided by, for example, fiducial markers in or on the floor.
Mobile drive units may use different mechanisms for loading, transporting, and unloading of payloads. One type of mobile drive unit waits until the payload is placed on or in the mobile drive unit's payload housing. To unload the payload, some mobile drive units use a lifting tray that pivots around one end of the tray to dump the payload, similar to how a dump truck functions.
Being able to monitor the status of payloads during transport, particularly which such payloads are not physically secured to the payload housing, is important. Further, mobile drive units sometimes encounter warehouse concrete floors that have irregularities, such as expansion joints or dips inherent in building process or caused by floor wear or damage.